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Commit 23067047 authored by Liam Breck's avatar Liam Breck Committed by Sebastian Reichel
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dt-bindings: power: supply: Add battery.txt with simple-battery binding 

Documentation of static battery characteristics that can be defined
for batteries that do not embed this data, which are required by
fuel-gauge and charger chips for proper handling of the battery.

The following properties are defined:
  voltage-min-design-microvolt
  charge-full-design-microamp-hours
  energy-full-design-microwatt-hours
  precharge-current-microamp
  charge-term-current-microamp
  constant-charge-current-max-microamp
  constant-charge-voltage-max-microamp

Property names are derived from corresponding elements in
enum power_supply_property from include/linux/power_supply.h
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/power_supply.h



Cc: Rob Herring <robh@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: default avatarMatt Ranostay <matt@ranostay.consulting>
Signed-off-by: default avatarLiam Breck <kernel@networkimprov.net>
Acked-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarSebastian Reichel <sebastian.reichel@collabora.co.uk>
parent e470f96f

Documentation/devicetree/bindings/power/supply/battery.txt

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Battery Characteristics



The devicetree battery node provides static battery characteristics.

In smart batteries, these are typically stored in non-volatile memory

on a fuel gauge chip. The battery node should be used where there is

no appropriate non-volatile memory, or it is unprogrammed/incorrect.



Upstream dts files should not include battery nodes, unless the battery

represented cannot easily be replaced in the system by one of a

different type. This prevents unpredictable, potentially harmful,

behavior should a replacement that changes the battery type occur

without a corresponding update to the dtb.



Required Properties:

 - compatible: Must be "simple-battery"



Optional Properties:

 - voltage-min-design-microvolt: drained battery voltage

 - energy-full-design-microwatt-hours: battery design energy

 - charge-full-design-microamp-hours: battery design capacity

 - precharge-current-microamp: current for pre-charge phase

 - charge-term-current-microamp: current for charge termination phase

 - constant-charge-current-max-microamp: maximum constant input current

 - constant-charge-voltage-max-microvolt: maximum constant input voltage



Battery properties are named, where possible, for the corresponding

elements in enum power_supply_property, defined in

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/power_supply.h



Batteries must be referenced by chargers and/or fuel-gauges

using a phandle. The phandle's property should be named

"monitored-battery".



Example:



	bat: battery {

		compatible = "simple-battery";

		voltage-min-design-microvolt = <3200000>;

		energy-full-design-microwatt-hours = <5290000>;

		charge-full-design-microamp-hours = <1430000>;

		precharge-current-microamp = <256000>;

		charge-term-current-microamp = <128000>;

		constant-charge-current-max-microamp = <900000>;

		constant-charge-voltage-max-microvolt = <4200000>;

	};



	charger: charger@11 {

		....

		monitored-battery = <&bat>;

		...

	};



	fuel_gauge: fuel-gauge@22 {

		....

		monitored-battery = <&bat>;

		...

	};